电弧增材制造不锈钢圆管短柱的几何特性和轴压性能

Geometrical characteristics and axial compression performance of stainless steel tubular stub columns fabricated by wire and arc additive manufacturing

为研究电弧增材制造(WAAM)不锈钢构件的受力性能,采用316L不锈钢材料,利用WAAM技术制作不同直径、高度和壁厚的圆管短柱试件,通过标准试件的拉伸试验获得材料基本力学性能;通过3D激光扫描进行几何测量,确定其几何参数和局部缺陷;通过短柱轴压试验,获得破坏形态,分析其与局部几何缺陷之间的关系,得到荷载-端部轴向位移曲线,进而分析轴压承载力的影响因素;并将轴压承载力试验结果与采用国内外钢结构设计规范预测结果进行对比分析。结果表明:相比普通钢管构件,WAAM圆管短柱的几何截面具有较大不规则性,局部几何缺陷也相对较大,最大偏差的平均值、最大值分别为0.27~0.75 mm、0.33~0.95 mm;轴压试验的所有WAAM圆管短柱均发生了局部屈曲,且屈曲最明显区域总体上对应于局部几何缺陷较大区域;WAAM圆管短柱的归一化轴压承载力为0.88~1.06,轴压承载力总体上随着径厚比的增大而降低,局部几何缺陷对承载力有一定影响;WAAM圆管短柱能达到欧洲EN-1993-1-4和美国AISC 370中所规定的轴压承载力要求,但多数试件无法达到我国DL/T5154—2002的轴压承载力要求。

In order to study the mechanical properties of wire and arc additive manufacturing(WAAM)stainless steel components,a group of tubular stub columns with different diameters,heights and wall thicknesses were fabricated by WAAM technology,and the basic mechanical properties of 316L stainless steel were obtained by tensile tests of standard specimens.Geometric measurements were carried out with 3D laser scanning to determine their geometric parameters and local imperfections.Through the compression test of stub columns,the failure mode was obtained and compared with the local geometric imperfection shapes.The load-end axial displacement curves were then obtained,and the axial compression capacity and the related influencing factors were analyzed.The test results of axial compression capacity were compared with the predictions from various steel structure design codes.The results show that compared with the conventional steel tubes,the tubular stub columns by WAAM have more dimension variations in the cross-section and larger local geometrical imperfections,and the average and maximum of the maximum imperfection deviations are 0.27-0.75 mm and 0.33-0.95 mm.Local buckling occurs in all tubular stub columns in the compression capacity tests,and the buckling region is close to the region with large local geometrical imperfections.The normalized axial compressive loading of tubular stub columns by WAAM ranges from 0.88 to 1.06.Generally speaking,the corresponding axial compression capacity decreases with the increase of the slenderness ratio,and the local geometric imperfections have a certain influence on the ultimate capacity.The tubular stub columns by WAAM can satisfy the ultimate capacity requirements of European code EN-1993-1-4 and American code AISC 370,while most specimens fail to meet the design axial compression capacity requirements of the Chinese Code DL/T 5154—2002.